ISO SPONGES 



[SUB-TRIBE EUTAXICLADINAE, Rff.] 



[FAMILY ASTYLOSPONGIDAE, Rff.]. * Astylospongia, Roem. [Sil.] ; 

 *Caryospongia, Rff. [Sil.] ; *Carpospongia, Rff. [Sil.] ; *Astylomanon, Roem. 

 [Sil.] ; *Caryomanon, Hinde ; *Palaeomanon, Roem. [Sil.] ; *Protachilleum, 

 Z. [Sil.] ; *Eosj)ongia, Bill [Sil.]. [FAMILY HIXDIADAE, Rff.]. *Hindia, 

 Duncan [SiL]. 



Incerti sedis. [FAMILY RHIZOMORIXA, Z. ( = CORALLISTIDAE + AZORI- 

 CIDAE)]. Genera *Cnemidiastrum, Z. [Jur.] ; *Corallidium, Z. [Jur.] ; 

 *Hyalotragos, Z. [Jur.] ; * Pyrgochonia, Z. [Jur.] ; * Discostroma, Z. [Jur.] ; 

 *Leiodorella, Z. [Jur.] ; *Epistomella, Z. [Jur.] ; * Platychonia, Z. [Jur.] ; 

 *Bolidium, Z. [Cret] ; *Astrobolia, Z. [Cret.]; *Chonella, Z. [Cret]; 

 *Seliscothon, Z. [Cret] ; *Chenendepora, Lamx [Cret.]; *Verruculina, Z. 

 [Cret] ; *Stichophyma, Pom. [Cret] ; *Jereica, Z. [Cret] ; *Coelocorypha, 

 Z. [Cret] ; *Stachyspongm, Z. [Cret] ; *Pachinion, Z. [Cret] ; *Nipterella, 

 Hinde [Cambr.] ; *Pemmatites, Dun. [Garb.] ; *Kagania, Stuck [Garb.]. 



GRADE II. MONAXONIDA, E. and D. 



Demospongiae with monaxon spicules, without admixture of 

 triaxon or tetraxon types. 



In the classification of this most difficult and perplexing group, 

 which exemplifies in the fullest degree the plasticity of the Demo- 

 spongiae, and the frequency of adaptive and convergent evolution 

 in this class, we follow the classification of Topsent [26 and 28]. 



ORDER 1. Hadromerina, Topsent 



Monaxonida, usually of massive form, sometimes stalked or cup-shaped. 

 Structure compact Skeletal framework radiate or without order, seldom 

 fibrous, non-reticulate. Spongin absent, or very feebly developed. Mega- 

 scleres monactinal or diactinal, usually of one kind only ; microscleres, 

 when present, asters or microrhabdi, never chelae or sigmata. 



SUB-ORDER 1. fAcicuLiNA, Tops. 



Megascleres diactinaL 



FAMILY 1. COPPATIIDAE, Tops. Microscleres absent, or in the form of 

 euasters, sometimes with the addition of streptasters. Spungosorites, 

 Tops. ; Anisoxya, Tops. ; Coppatias, Soil. (incl. Astropeplus, SolL ; and 

 Dorypleres, Soil.) ; Magog, SolL ; Hemiasterella, Crtr. ( = Epallax, Soil.) ; 

 Asteropus, Soil. FAMILY 2. STREPTASTERIDAE, Tops. Microscleres strept- 

 asters ; no euasters. Genera Amphius, SolL ; Scolopes, Soil. ; Trachy- 

 cladus, Crtr. ; Rhaphidistia, Crtr. ; Spiroxya, Tops. ; Holoxea, Tops. 

 FAMILY 3. ITETHYIDAE, Gray. Globular or massive, with radiating 

 framework and differentiated ectosome ; microscleres, when present, 

 typically euasters. Genera jTethya, Lam. [Eoc.], (Fig. 30, A) ; Tcthyor- 

 rhaphis, Ldf. ; Tuberella, Keller (Fig. 30, B) ; Trachya, Crtr. ; Heteroxya, 

 Tops. FAMILY 4. STYLOCORDYLIDAE, Tops. Pedunculate ; framework, 



